Rolls having their cylindrical surface formed by a resilient material cover, for example a rubber covered wipe roll as used in flexographic printing, at times develop flat spots, or areas, on the surface. It is believed this occurs when the surface is distorted, or flattened, for too long a period of time, e.g. during transportation. It has been customary to dial the surface of these rolls with a dial instrument to test for concentricity before use. However, such dialling does not necessarily detect any flat spots in the cylindrical surface. Such flat spots are usually only detected after the roll is assembled in a printing machine and printing commenced; any flat spot then becomes apparent, as it creates an area of over inking of the material being printed, e.g. corrugated container blanks. The defective roll then has to be removed from the printing machine and replaced. It may be possible to salvage the defective roll after removal by re-grinding a new surface.